Heating and cooling system



Nov. 9, 1954 L. MARCHANT ETAL HEATING AND COOLING SYSTEM 10 Sheets-Sheet 1 Filed May 6, 1949 Hun-H -nh.

w m m a M Nov. 9, 1954 L. MARCHANT ET AL 2,693,939

HEATING AND COOLING SYSTEM Filed May 6, 1949 10 Sheets-Sheet 2 ATTORNEYS Nov. 9, 1954 L.-MARCHANT ET AL HEATING AND COOLING SYSTEM 10 Sheets-Sheet 3 Filed May 6, 1949 I 7 1 I I I I/ I! I I I I I r P I z z l I v I I I n I I I I 1 I I I I I I I 2 J I I w" I I I I I I I I I b I I I w I I I I I I II I I I I I I/ I 2 I I w/ n I I I I I I I I I 1 I 1 I1! I I n I I. I I I I I I f I I I I I I I I z Nov. 9, 1954 MARCHANT ETlAL 2,693,939

HEATING AND COOLING SYSTEM Filed May 6, 1949 10 Sheets-Sheet 4 TORNEAS Nov. 9, 1954 L. MARCHANT ET AL 2,693,939

HEATING AND COOLING SYSTEM Filed May 6, 1949 10 She ets-Sheet 5 'II// E BY [en's I4 Nov. 9, 1954 L. MARCHANT ET AL 2,593,939

HEATING AND COOLING SYSTEM Filed May 1949 l0 Sheets-Sheet 7 Lewis Aid/aha! 6A'TTORNEY5 10 Sheets-Sheet 8 MARCHANT ET AL HEATING AND COOLING SYSTEM oRNEA's NVE E Nov. 9, 1954 Filed May 6, 1949 United States Patent HEATING AND COOLING SYSTEM Lewis Marchant, Wildwood Crest, N. J., and Edward E. Bratton, Upper Darby, Pa.

Application May 6, 1949, Serial No. 91,658 14 Claims. (Cl. 257-3) Our invention relates to systems of and methods for heating, cooling and/or air-conditioning, and components of such systems.

A purpose of our invention is to provide such a sys tem or method having improved efficiency, economy, and convenience.

A further purpose of our invention is to provide a heating system or method which makes a highly effec- Live use of radiation from the sun as a majorsoui'ce' of eat.

A further purpose of our invention is to provide a heating system or method which takes heat from solar radiation when available, stores it, and delivers it when needed.

A further purpose of our invention is to provide a heating system or method which can take heat from solar radiation at realtively low temperature during periods of low intensity of such radiation and utilize such heat at higher temperature.

A further purpose of our invention is to provide an improved and efiicient ground heat exchanging system having high thermal conductivity, thus permitting'the use of the earth as a source of. heat when needed, and as a place into which heat can be put for temporary storage, or for gradual discard when necessary.

A further purpose of our invention is to provide an air conditioning system automatically modulated in proportion to requirements for heating or cooling.

A further purpose of our invention is to provide an automatically heated or cooled water supply for household, industrial or other requirements.

A further purpose is to make the adjustment of our system responsive in a predetermined way to conditions of radiation and/or ambient temperatures prevailing at any particular time. i

A further purpose is to have aheating, cooling and/ or air conditioning system utilizing a powered mechanicalrefrigeration cycle which needs to operate only during the off-peak periods of the power source.

Other purposes will appear in the remainder of the specification and from the claims.

in the drawings, we have chosen to illustrate some only of the numerous particular embodiments in which our invention may appear, the forms shown being chosen from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.

Figure 1 is a diagrammatic representation of a form of our invention. Figure 2 is a cross section along the line 22 in Figure 1 of the heat exchanger there. Figure 3 is a longitudinal section taken somewhat to one side looking toward the center of the refrigerant outlet valve chamber of the hot water heater shown in Figure 1.

Figure 4 is a somewhat diagrammatic cross sectional view, sectioned thru the air intake, of a solar unit in accordance with our invention, shown for the sake of simplicity and clarity without the fins on the back of the solar sheet and without the supporting structure for the glass. Figure 5 is a fragmentary perspective view, broken away, of the unit as shown in Figure 4;

Figure 6 is a sectional view of a part of. this unit. including fins, taken longitudinally of the heat transfer fluid tubes. Figure 7 likewise is a sectional view of a part of this unit including fins but taken across the fluid tubes. Figure 8 is a sectional view similar to Figure 7, but of a somewhat different form of unit.

Figure 9 is a fragmentary sectional view of a joint 2,693,939 Patented Nov. 9, 1954 between transparent panels of the unit, together with supporting structure but omitting the solar sheet. cuts the panels in a plane perpendicular to them along a line perpendicular to the length of the joint.

Figure 10 is a vertical section of a solar coil expansion valve in accordance with our invention.

Figure 11 is a cross sectional view of an expansion valve such as is used elsewhere in our invention.

Figure 12 is a longitudinal section of a differential pressure switch in accordance with our invention.

Figure 13 is a vertical longitudinal section of a temperature modulation controller in accordance with our invention.

Figure 14 isa diagrammatic view of an alternative form of our solar unit and the air duct leading therefrom. V

Figure 15 is a vertical section through the lower part of the earth tube shown in Figure 1. Figure 16 is a cross section along the lines 1616 in Figure 15.

Figure 17 is a diagrammatic fragmentary view of an alternate form of our system.

Figure 18 is a diagrammatic fragmentary view showing a form difiering somewhat from that of Figure 17.

Figure 19 is a fragmentary perspective View of the pipes in and near the cellar floor which are shown in Figure 17.

Figure 20 is a sectional diagrammatic view showing the thermostatic control for moistening the ground, which is preferably a part of our invention whether in the form of Figure l or of Figure 17 or 18, but is here shown as it would be applied in connection with the form of Figure 17 or 18. For simplicity and clarity of illustration, refrigerant pipes are omitted from this view, and the control box and its elements are exaggerated.

Figure 21 is a horizontal cross section, partly broken away, looking downward, of a somewhat dififerent form of cellar floor heat exchanger. Figure 22 is a vertical section along lines 22-22 on Figure 21.

Figure 23 is a cross section on a larger scale of the refrigerant pipe of Figure 21 showing the detail thereof including fins to facilitate heat exchange.

Figure 24 is a fragmentary diagrammatic view of a somewhat different form of our invention.

Figure 25 is a diagrammatic view, greatly simplified for clarity of illustration, of another somewhat different form of our invention.

Figure 26 is a vertical section corresponding to Figure 7, but showing an alternate form of solar coil, sheet and insulating cover combination.

Describing the invention shown, by way of illustration and not in limitation:

As shown especially in Figures 4, 5, 6 and 7, solar unit 31 has a metal solar-radiation-absorbent sheet 32. Preferably on top of this sheet is solar coil 33, which is intimately attached to the sheet in some fashion such as welding or brazing, so as to allow heat to pass'freely from sheet to coil. Another possible arrangement would be to have the coil on the bottom side of the sheet.

Solar coil 33 is a hollow serpentine pipe through which refrigeration-type fluid such as Freon can circulate to absorb heat which the metal has received from radiation, especially from the sun. In tion the refrigerant fluid will preferably be substantially completely evaporated.

It will be understood that the coil could take other forms than that of the serpentine pipe; for example, it could be a grid of pipes.

The sheet and coil are preferably of a metal which is a good heat conductor, such as copper, and it is desirable that they be blackened and roughened on the side toward the sun so as to absorb a maximum of the radiation which falls on them. They should preferably be so positioned as to get a maximum total solar radiation during the colder part of the year, when most of the heating has to be done. Thus, for winter heating of buildings, such as homes, in the northern hemisphere, a very desirable location is on the roof of the building facing south and inclined from the horizontal at an angle which will depend on the latitude. At latitude 40 north this would preferably approximate 45.

Above sheet 32 and solar coil 33 are covers 34 and 35, one above the other, each made of some material,

this process of heat absorpsuch as glass, which is transparent to most of the solar radiation. They are spaced from each other and from the coil and sheet, and at their edges they abut on relatively air-tight, heat-insulating surrounding partition 36, with which they form tight joints, details of which are not shown, but which could, for example, involve having the covers rest on a flat ledge of the partition, with suitable sealing material applied over them at the joint. The surrounding partition extends down below the sheet, with which it also forms a tight joint. Thus space 37 between covers and space 38 between cover and sheet are more or less dead air spaces to provide heat insulation for the sheet and the solar coil and thus prevent undue heat loss by conduction or convection to the outdoor atmosphere.

Each transparent cover will preferably consist of a series of panels side by side, each panel being made up of two individual overlapping glass panels which are in contact with each other where they overlap. Thus, in panel 39 of upper cover 35, lower pane 40 extends from lower strip 41 of partition 36 up to anintermediate point of the cover, and upper pane 42 extends down from upper strip 43 of partition 36 to overlap the lower pane 40 at 44. Likewise, in panel 45 of lower cover 34. lower pane 46 and upper pane 47 overlap at 48.

A preferred method of joining these panels is shown in Figure 9. Rods such as 49 are supported in an upright position in any suitable fashion, as for example by passing their reduced ends as bolts through partition 50 of the solar unit below sheet 32 (not shown in that figure) which in such case will have holes for the rods to pass through. Supported on top of the rods is inverted T- rib 51, the horizontal arms of which in turn support both the lower panes of panels 45 and 52 and also, with the help of fillers 53 and 54 lying on top of the arms, the upper panes of those panels.

A plurality of bolts such as 55, each threaded at both ends, rest on top of the shank of the T-rib 51, supporting angles 56 and 57 on opposite sides of that shank. Nuts on opposite ends of the bolts hold the angles tight against the shank, using rod 58 lying between the tops of the angles as a fulcrum. Upper panels 39 and 59 are supported by the angles in the same way as the lower panels are supported by the T-bar. Sealing material 60 helps make a tight ioint, and the cap 61 rests on top.

These joints make it possible to open up the solar unit from the top without undue inconvenience whenever cleaning, repair or overhaul of the interior of the unit is desired. Furthermore, a single panel can be removed,

as for example to replace the glass, without disturbing the remaining sections.

As shown in Figure 1, solar coil 33 forms part of a heat pump which is adapted to take heat from the solar unit for utilization, as for example in heating a building or in heating water or other media for various purposes, such as domestic uses, or process heating as in the evaporation or concentration of such liquids as milk, juices, dye extracts or brines. In so doing, the heat pump acts on a certain medium of the mechanical refrigeration type, such as the Freon already mentioned, which is capable of acquiring and surrendering heat to transfer heat from the solar unit to a desired location for utilization. In the solar coil the refrigerant undergoes the step in the heat pump cycle in which the input of thermal energy causes large increase of entropy a step which, as already indicated, preferably causes substantially complete evaporation.

From the vapor end of the solar coil, which is preferably enlarged to form vapor header 68 (Figure 4), the fluid passes through pipe 69, three-way valve 70, and cold vapor pipe system 71 into heat exchanger 73, where it picks up heat from hot refrigerant liquid on the high pressure side of the system. This heat exchanger will preferably be approximately cylindrical, with the refrigerant liquid passing from inlet header 74 through tubes 75 into outlet header 76, while the vapor comes into the central space near the outlet header by Way of inlet 77, and leaves near the inlet header by way of outlet 78. As shown in Figure 2, the inlet and outlet are each placed well oif center at more or less of a tangent to the periphery of the space and with the one opening into and the other away from the space in the same rotational direction, so that the vapor tends to pass in helical flow through the central space over the tubes, thus increasing the rate of heat exchange.

Any slugs of liquid which may have happened to pass out of the solar coil along with the vapor will be trapped in the bottom part of this heat exchanger tank, and prevented from proceeding further and possibly damaging the compressor. Compressor oil which collects in the heat exchanger can be removed by drain pipe 79 for return to the compressor.

From heat exchanger 73 the refrigerant vapor passes through warm vapor pipe 86 into compressor 87, by Whose action it is raised in pressure and temperature.

It leaves the compressor in hot vapor pipe system 88 and from this is supplied through three-way valve 90 to air coil 91. In the air coil, the vapor will condense, giving up heat to air passing through, which air can in turn be used for heating purposes, as in warming a building, for example.

The hot liqiud resulting from condensation of hot vapor in air coil 91 passes through three-way valve 92, hot liquid outlet piping 93, outlet valve unit 94 and hot high pressure liquid pipe system 95 into heat exchanger 73, where, as already indicated, it warms the low pressure vapor which is proceeding toward the compressor. After passing through the heat exchanger, the high pressure liquid, now reduced in temperature, proceeds through cold liquid pipe system 96 and stop valve 97 into expansion valve 98, where its pressure is reduced. From the expansion valve it passes through three-way valve 99 and back into solar coil 33, the inlet end of which preferably forms liquid header 100 (Figure 4). It thus completes its heat pump cycle using the solar coil as evaporator.

Also connected across between hot vapor pipe system 88 and hot liquid outlet piping 93 is hot water supplytank 102, preferably a vertically positioned tank rather similar in construction to an ordinary tube-type heat exchanger. The vapor in this tank passes from inlet header 103 to outlet header 104 through tubes 105, where it condenses, imparting heat to water in the tank surrounding:

the tubes, and thus furnishes a hot water supply for domestic and other purposes.

it will be noted that as described and shown, there is no valve used between hot vapor pipe system 88 and the hot water supply tank. A valve at this point might of course be put in for convenience in case of repair and overhaul, but during normal operation this connection is preferably kept open at all times. Thus the water will be heated whenever its temperature falls below that of the hot high pressure refrigerant vapor. Furthermore, whenever demands elsewhere tend to cause the hot high pressure refrigerant vapor temperature to fall below the temperature maintained within the hot water heater,

refrigerant condensate within that heater will flash into vapor to help maintain the hot high side refrigerant vapor temperature and pressure. be required to function so frequently to maintain hot high side refrigerant vapor temperature and pressure against sudden temporary demands, and the economy of operation of the system will be considerably improved.

Also, with sufficient heat storage capacity in the hot water system relative to the heating needs of the installation, it will be possible also to regulate the system as a whole so that compressor operation can be confined to periods outside of the peak periods of power consumption, thus greatly reducing the cost of electricity to operate the compressor. During periods when the compressor is kept out of operation, the hot water will continually be evaporating refrigerant in the hot water supply tank, which refrigerant will condense in the air coil to heat the air for utilization in heating and will then flow back to replenish the refrigerant liquid in the hot water supply tank. It will be understood that for such replenishment, the system must be made so that such flow will be induced, either by gravity, as in the form shown, or by some pumping means.

In the outlet valve unit 94, as shown in detail in Figure 3, refrigerant coming in from the air coil 91 and hot water supply tank 192 through hot liquid outlet piping 93 causes the liquid level in the valve unit tank 106 to rise bringing up ball 107 until ball lever 108 through the move- Thus the compressor will not the hot water supply tank, independently of the level at points beyond the valve.

In the preferred form of our heating system, we have provided for use of the earth as a place to store heat during periods in the heating season when more heat is available to the solar radiation heat receiver than is needed for immediate heating purposes, and for later removal of stored heat from the earth, and utilization of it, during periods when insuflicient heat is available directly from the solar radiation heat receiver.

To effectuate the heat storage in the earth, hot highpressure refrigerant vapor pipes system 88 is connected to three-way valve 121, from which refrigerant pipe 122 leads to earth tube 123, where the refrigerant condenses, imparting heat to the earth 124 in the immediate neighborhood of the tube. From the earth tube the refrigerant passes through pipe 125 and three-way valve 126 into hot refrigerant liquid pipe system 95. Thus, with proper setting of the three-way valves, the earth tube can be operated as a condenser to store heat temporarily in the earth. 1

To remove the heat from the earth for use when needed, cold high pressure refrigerant liquid pipe system 96 is connected to expansion valve 127, which in turn is connected through pipe 128 to three-way valve 126 on one side of the earth tube, while three-way valve 121 on the other side of the tube is connected to cold refrigerant vapor pipe system 71. Thus with another setting of the three-way valves, the earth tube can be operated as an evaporator to pick up heat from the earth for ultimate utilization in the same way that heat from the solar coil is di rectly utilized, through the action of the heat pump circuit, which in turn gives heat to the water in the hot water heating tank 102 and to the air passing through in heat exchange relation with the air coil 91. I

Thus it is possible to take heat from the solar radiation heat receiver and store the excess not used in the building in the earth close to the earth tube, and then to draw on the heat thus temporarily stored at times when insufiicient heat is being received in the solar coil.

Because of the relatively high temperature at which this heat can be stored, the coefficient of performance of the system using such heat can be much higher than 1f the system were forced to rely wholly on the heat normally already in the earth, at the. relatively low temperatures which would then prevail, considering especially that withdrawal of heat without replenishment tends to force down the immediately adjacent earth temperatures,

having a cumulative effect during the heating season.

The earth tube preferably extends more or less vertically to a distance on the order of 5 to 25 feet into the ground.

The detail of its interior is shown in Figures 15 and 16. It consists of three tube walls, one inside another, providing corresponding passageways, the outermost tube wall 135 having vanes 136 to facilitate heat transfer with the earth. Intermediate tube wall 137 does not extend so far down as either of the others, so that there is intercommunication near the bottom between outermost passageway 138 and intermediate passageway 140, despite the fact that these two passageways are collectively sealed ofi from the earth by partition 141 at their bottom. Thus refrigerant will pass down intermediate passageway 140,

and then into and up outer passageway 138 or vice versa.

innermost passageway 142 is connected by pipe 143 (Figure l) to a water source (not shown). Through its open end in the center of the polnted bottom of the earth tube, moisture can be supplied to the earth. Such water, moistening the earth and preventing it from dryrng out.

will facilitate heat exchange between the earth tube and the earth in contact with it by increasing the rate at which heat passes through the earth nearby in response to temperature gradients imposed by the refrigerant 1n the earth tube. The efliciency of heat transfer in such earth contacts and thus the eflicrency of any system relying on such contacts depends to a great degree on the nance of ro er moisture in the earth. i l fl rough for Zhe sake of simplicity of illustration only one such earth tube is shown, it Wlll be understood that a number of such earth tubes, connected in parallel, and spaced apart as desired, can (and probably with thls forn; in most cases would) be used, depending upon the therma requirements of the particular installation involved. I d

Instead of the earth tube, it may often prove more a vantageous to circulate the refrigerant througr pipes lpsr passages in exterior contact with, or in, bud mg wa foundations or floors which are in contact with the earth, for example the cellar floor. under many circumstances be simpler and cheaper to construct. Preferably a wall or floor will be selected that is more heat conductive than the adjacent earth. However, even where the material in the wall or floor is'not as heat conductive as the earth, heat exchange with the earth is still likely to be improved. The pipe and the wall or floor can be kept in closer contact than pipe and earth, because the earth tends to lose contact with a pipe due possibly to temporarly freezing of moisture causing separation between them. The area of contact between the wall or floor and the earth is enormously greater than that between pipe and earth.

In the form shown in Figure 18, the refrigerant passes through cellar floor coil system 149 (the end of which is shown broken away) on the way between three-way valves 121 and 126, which correspond in function and in position relative to the rest of the refrigerant system to the previously mentioned valves 121 and 126, respectively. In the condensing phase, the refrigerant will pass through vapor header 150 and thence to liquid header 151 by way of a plurality of pipe loops 152 connected in parallel across between the two headers. The horizontal parts of these pipe loops are embedded in cellar floor 153, preferably of concrete of relatively good heat conductivity, so that the refrigerant on condensing gives up heat which passes through the pipe into the floor and thence into the adjacent earth. orating phase, the flow of refrigerant is reversed.

Instead of having the refrigerant and the earth exchange heat thus by more or less direct conduction, it is advantageous in some ways to use a brine circulation system as an intermediary, as in Figure 17, where the refrigerant runs through heat exchanger 155 between three-Way valves 121' and 126 and there imparts heat to, or receives heat from, brine circulating system 156 (shown with one end broken away). This circulating system employs pump 157 to circulate the brine between heat exchanger 155 and the place where heat is exchanged with the earth. In the drawing, piping for the heat exchange with the earth is shown as along similar lines to that for the refrigerant in Figure 18, though it would also be possible to employ such a brine intermediary with the brine using an earth tube like that in Figure 1, for example. away, the tube skeleton used for the brine in Figure 17, with its two headers 158 and Also shown in Figure 19, with one end broken away, is the tube skeleton 161 for use in moistening the ground in the forms of Figures 17 and 18. leads to branch pipes 166 and 167, the lower parts ofwhich, 168 and 169, respectively, are preferably in, on or under the floor 153 (Figures 17 and 18); and from there the water passes thru moisture nozzles 170 opening into the ground. This permits moistening the ground adjacent the floor to facilitate heat transfer between floor and ground. Above the concrete floor and 18) may be placed moisture-proof barrier 172 of any suitable material impervious to moisture to keep the ground moisture out of the cellar, passage for the various piping which has already been mentioned.

The supply of moisture to the ground in these devices should preferably be controlled in some manner. While this control may be a simple manual control, it is preferably done automatically by the thermostatic moisture control unit 173 shown in Figure 20. Thermostatic bulb 174 is buried in cellar floor 153, while thermostatic bulb 175 is buried in the earth at a little distance from the floor, as for example two feet below. Thermostatic bulb 174 is connected by capillary tube to lows 178; and thermostatic bulb 175, to Sylphon bellows The two Sylphon bellows, both of which are 'en closed in valve box 180, have rods 181 and 182, respectwely, connected to opposite ends of valve arm 183, WhlCh they tend to rotate in opposed directions. the center of the valve arm is attached the movable part This arrangement would.

In the evap Figure 19 shows, broken 159 and pipe loops 160.

Water pipe 165;

153 (Figures 17 but of course allowing Sylphon bel- Tov well 190. The other end of the spring is connected to spring seat 191, made adjustable by connection to adjustment screw 192.

By providing gas in the respective therrnobulbs to 've equal gas pressure in the bellows when the temperatures of the two thermobulbs 174 and 175 are equal, so that the two bellows will counterbalance each other, and by adjusting the spring to be in neutral position exerting neither tension nor compression on the rod when the valve is in closed position, the valve will be in closed position when the temperature gradient between the thermobulbs is zero. However, when the temperature gradient between the thermobulbs becomes too great, the imbalance between the forces of the two bellows will be suflicient to push the valve arm around against the tension or compression of the spring to a point where the valve will be open and water will flow to be dispensed in the ground, moistening it by'a combination of capillary attraction and gravity flow. The moistening of the ground, by improving conductivity and reducing the temperature gradient, will reduce the imbalance between the two bellows, thus permitting return of the valve to closed position under the force of the spring.

A less desirable alternative would be to simply have the thermobulbs connected to temperature indicators as an aid to intelligent hand regulation.

Automatic moistening control similar to that shown in Figure 20 can be used also on the earth tube (123) in Figure l, in which case one of the thermobulbs would preferably be in firm and extensive contact with the outside of the tube near its bottom, and the other preferably at a suitable distance away in the ground.

Figures 21 through 23 show a form in which heat exchange between the refrigerant and the earth is effected by running the refrigerant between three-way valves 121 and 126 (not there shown), through heat exchanging tube 201 which is located in trough 202 built into one side of the cellar floor 203 under removable moisture-proof cover 204. Trough 202 is filled with water which is being pumped up through outlet pipe 205, and taken (by a pipe not shown) over to inlet pipe 206 into trough 207 built into the floor on the other side of the cellar, under removable moisture-proof cover 204'. From there it circulates through ducts 208 built into the cellar floor under moisture-proof barrier 209 back to trough 202. Thus heat to be stored in the earth can be taken from the refrigerant tube 201, operating as a condenser, into the water, thence into the cellar floor and from there into the earth. On the other hand, when it is desired to utilize such stored heat it is possible by a different setting of the three-way valves to operate the refrigerant tube 201 as an evaporator to receive heat coming from the earth by way of the floor and water.

In addition to the features of the solar unit (Figures 4 through 8) which have already been described, which enable it efiiciently to get heat from radiation, especially solar radiation, and to use such heat for an evaporator in a heat pump, solar unit 31 has provision also for using such heat to heat air in the unit for heating purposes outside the unit, whenever the radiation is sufiicient to produce temperatures high enough to make this practicable.

To effectuate this, the solar units radiation-absorbing sheet 32 is in direct contact, on the opposite side from the sun, with air in air passageways 220, of which the sheet forms one side. Fins 221 (Figures 6 and 7) preferably of highly heat-conducting metal, intimately attached (as by soldering) to sheet 32, extend downward to form the sides of the air passageways and thus to increase the heated metal surface with which the air can make contact. The bottom of the passageways is formed by partition 50 (Figure 4), preferably of some such material as plywood.

In order to increase heat transfer between metal and air, the passageways may desirably be transversely corrugated on one or more sides in order to cause turbulence in the air flowing through the passageways. An illustration of this is in the alternate form shown in Figure 8, in which the solar-radiation-absorbing sheet 223 which is employed is corrugated for this purpose, the horizontal tubes of solar coil 33 being in the troughs of the corrugated sheet.

The air heated in the passageways under the radiationabsorbing sheet then flows into warm plenum 224, located between walls 225 and 226 which support the higher end of the face of the solar unit on flat roof 227. Insulation 228 in these walls and in those closing off the ends of the plenum, of which only 229 is shown, prevents undue heat loss from this plenum.

From the warm plenum the air passes through outlet opening 230, as indicated by the arrows, into downward air tube 231 (Figure 1) across through fan tube 232 to fan 233, which supplies the motive power to draw the air along this course. In installations in houses which formerly used conventional heating systems, it may prove very convenient and inexpensive to make the bore of the chimney, 234, (Figure 14), serve as all or part of the downward tube, or to run the tube through the bore if for any reason it proves undesirable to use the original wall surfaces of the bore.

From the fan the air is driven through tube 235 and air coil housing 236 from which it emerges to heat the house or other building.

In the form shown in the figures, for simplicity of illustration we have the air which heats the house simply filtering up through the house without use of ducts, more or less in the way that heating is accomplished in the case of the so-called pipeless heater." Instead of this, it will be understood that our invention could use other modes of using the air for heating purposes, such as a complete set of ducts to introduce the heated air into the individual rooms as in the case of more typical modern air heat, or ducts leading into the walls and floors to furnish radiant heat, or both.

In any event, the system is arranged so that the air eventually reaches intake opening 238 in the solar unit (Figures 4 and 5), from which it passes through passage 239 into cold plenum 240, from which it reaches air passageways 220 again.

The refrigerant system is so arranged that when the heat being received into the air circuit from the radiationabsorbent sheet is more than is needed to heat the build: ing, air coil 91 may be operated evaporating to pick up some of it for temporary storage in the earth. The refrigerant for this purpose is admitted from cold liquid pipe system 96 through expansion valve 242 (Figure 1) into three-way valve 92, from which, when the valve is properly set, the refrigerant reaches air coil 91. There it evaporates, absorbing excess heat from the air, and then passes through three-way valve 90, into the low pressure refrigerant vapor pipe system 71. Once the heat is in the refrigerant in this pipe system, its temporary storage in the earth follows the same process as that for heat which has come in refrigerant from the solar coil.

Damper 244 (Figure 4) makes it possible to shunt the air away from the radiation-absorbent sheet 32 during periods when insulficient radiation is being received by the sheet, or when it is not desired to heat the air. When the damper bottom swings to the opposite side of opening 238, the air is shunted directly into the warm plenum, which it traverses to outlet opening 230, and thence through the duct, fan and air coil and back into the house as before. Thus the air circulation system can continue to be used for ventilation, and for heating by means of the condenser in the air coil, without passing the air next to the radiation-absorbent sheet of the solar coil.

Fresh air as desired for hygienic reasons and to replace leakage losses may be admitted into the air circuit in any of a number of places. In the form shown it is done by opening door 245 directly under air intake opening 238 through which air is constantly being sucked into the solar unit by the operation of the air circulation fan 233. The door gets its fresh air through duct 246. The door may be set manually to admit a more or less constant proportion of fresh air.

In case sufficient snow or ice should be deposited on the solar unit to seriously diminish the access of the heat receiver to radiation, hot vapor pipe system 88 has been connected to three-way valve 70 on the vapor side of the solar coil, and three-way valve 99 on the liquid side of the solar coil has been connected to hot liquid pipe system 95. This makes it possible by proper setting of the three-way valves, which should be operated in tandem, to run the solar coil as a condenser for the purpose of melting the snow or ice. Electrical connections 247 controlled by manual switch 248 have been provided as a suitable way to change these two three-way valves simultaneously over from evaporating to condensing position when desired.

The solar unit in the form shown provides for a sheet oriented and sloped to provide maximum heat receipt uid passing out into hot liquid pipe 93.

by a given area of solar-radiation-absorbent sheet used in connection with a building having a flat roof. It will be understood that by having a building with a sloping roof of the proper position and slope, a similar result can be achieved by a solar unit whose absorbent sheet is more or less parallel to the roof and can therefore be laid on right above, or built into, the roof. in such case, suitable duct arrangements can take the place of the plenums.

It will be understood that in making a solar unit it may under a particular set of circumstances be advantageous as a practical matter to construct the solar unit so that the solar-radiation-receiving sheet presents an angle toward the sun that is less than optimum, as far as radiation received per unit surface is concerned, so long as the radiation received per unit surface is sufiicient for the purpose. Thus, with a particular type and position of roof at a particular lattitude, under a particular state of relative costs of the diiferent elements of the solar unit, it may prove economical to have the radiation-receiving sheet parallel to or built into the roof, to save the cost of the walls, even though the particular roof is not positioned and sloped so as to make this optimum from the standpoint of the amount of radiation received per unit surface. Esthctic considerations may also afiect this matter.

A variation in the form of solar unit is shown in Figure 26. Instead of having the solar coil on top of the radiation-absorbent sheet and above them the transparent covers separated from each other and from coil and sheet, it has the solar coil 33' in intimate contact with the sheet 32' on its underside, and resting on top of the sheet to cut down convection and conduction losses is a relatively thick slab 249 of transparent heat-resisting and heat-insulating plastic such as a polystyrene solution of an unsaturated polyester or of an alkyd, described for example in the pamphlet Paraplex for Laminating, Molding, and Casting Applications, issued by Rohm and Haas Company, The Resinous Products Division, Washington Square, Philadelphia, Pennsylvania. Even though such a plastic would have considerably less heat conductivity than the glass which would be likely to be used in the other form, it would be desirable to make the total thickness of plastic here considerably more than that of glass in the other form, to help make up, from the heat insulation standpoint, for the absence of the intermediate air spaces in this form.

Instead of the plastic being directly on top of the metal sheet, it may be advantageous to space it slightly, as for example, one eighth of an inch, by some convenient means, such as the insertion in between them of washers held in position by screws through the plastic, or by bosses on the bottom of the plastic.

Instead of a single solar unit, the system may have two (or more) solar erant systems in parallel, as shown in Figure 14. Here some of the refrigerant from three-way valve 99 will continue on through stop valve 251, solar coil 252 in solar unit 253, and stop valve 254 to three-way valve 70, while the rest of the refrigerant passes through stop valve 255, solar coil 256 in solar unit 257, and stop valve 258 on its way between the three-way valves. some of the air goes through inlet 259 into solar unit 253, then through outlet 261 controlled by damper 262, and into tube 263; While the rest of it goes through inlet 264 into solar unit 257 and then on through outlet 265 controlled by damper 266 into tube 263. With such an arrangement, it is possible by use of the individual stop valves and dampers to take one of the solar units temporarily out of the air and refrigerant circuits for cleaning or repairs while the system continues operating at reduced capacity with the other solar unit.

In Figure 24 we have shown a variation in our heating system in which, instead of running the refrig erant through the air coil from which air is supplied to heat the building, for example, we run it through a large brine tank, which serves as a means of heat exchange and heat storage. High temperature refrigerant vapor from pipe 88 runs in through large brine tank 269, there condensing and giving up heat to brine, the refrigerant liq- Using appropriate pipes of which an example is shown, brine is drawn from the tank through three-way valve 270 by pump 271 and driven to circulate through air coil 272 and three-way valve 273 back into the tank, and will also circulate as desired through radiators schematically represented by units connected into the air and refrig- Likewise,

advantage of reduced rates available for off-peak operation. The brine tank also furnishes a reserve of heat to fall back on in case it should be desirable or necessary for any other reason temporarily to stop running the refrigerant circuit at a time when the direct air circuit is not functioning.

Another variation is shown in Figure 25. Here a heating system which corresponds to that in Figures 1, 17 or 18 is represented schematically by such of its more prominent features as solar coil 33, compressor 87, air coil 91 and earth exchange 284. In the position in the refrigerant system occupied by the refrigerant part of hot water supply tank 102 in Figure 1, across between the hot refrigerant vapor pipe system 88 and hot refrigerant liquid outlet piping 93, is connected coil 285 in Glaubers salt tank 286. Through this tank, which as indicated contains Glaubers salt (sodium sulfate dekahydrate; Na2SO4'10H2O), also passes water piping 287 in hot water system 288. From the water piping in the tank, the hot water passes through pipe 289 into hot water tank 290. This tank through outlet pipe 291 supplies domestic hot water supply pipe 292 and hot water heating pipe 293 which is connected for example with radiators (not shown) for heating purposes. The heating water comes back by return piping 294 leading to both tanks and having cut-off 295 through by-pass valve 296 for mixing purposes into outlet pipe 291 to permit moderation of temperature of the Water in that pipe if and as desired.

In this form of heating system, the refrigerant coil in the Glaubers salt tank will usually run as a condenser to impart heat to the Glaubers salt, which in turn will pass it on to the hot water system for utilization for heating purposes. However, whenever, for example in order to reduce electricity costs by keeping shut down during peak periods, or to effect repairs, it is desirable to shut down the compressor for a limited period, during which the refrigerant cannot receive heat in the usual way, the Glaubers salt, with its high heat storage capacity will serve a dual function. It will not only continue to furnish heat to the hot water system, but, after the refrigerant liquid in the coil falls below the Glaubers salt in temperature, it will also evaporate the refrigerant to furnish refrigerant vapor for use in the air coil.

In addition to providing a very eifective way of heating, our system and method can, and preferably would, also provide for cooling and would preferably form the basis of a complete air conditioning system, for all year round service.

In the form of Figure 1, to meet cooling'requirernents for the building, the air coil 91 can be run evaporating, to take heat from the air before it passes through the building. In itself, this involves the same refrigerant connections as when the air coil is run evaporating to take heat for temporary storage in the earth, but will normally take place at a time, such as 'in the heat of summer, when the solar coil is shut oif from the refrigerant circuit and the damper 244 is set to by-pass the passageways under the radiation-absorbent sheet.

In the brine-tank form of Figure 24, cooling can preferably be achieved by having a separate cooling tank 305 cooled by the evaporation of refrigerant passing from cold high-pressure refrigerant liquid pipe system 96 through expansion valve 306 into a cooling coil 306' in the tank and discharging into cold low-pressure refrigerant vapor vpipe system 71. With proper setting of the three-Way valves 270 and 273, pump 271 will circulate brine which has been cooled in tank 305 through air coil 272 by means of appropriate pipes as shown.

It will be understood that whatever else is desired for the purpose of complete air conditioning, such as an air filter, apparatus for humidification -or dehumidification, and apparatus for sterilization, may be placed in a position to perform its function on the air being circulated by the fan before the air debouches into the building interior; it may, forexample, be placed within housing 236, where the circulating air also comes into contact with the air c011.

If desired, the refrigerant circuit may also be used for other cooling functions. Thus the refrigerant can be used to operate a low temperature evaporator to cool drinking water for use in the house. As shown in Figure 1, cold high pressure liquid from pipe system 96 is reduced in pressure in expansion valve 307, evaporates within evaporator coil 308 cooling the Water in the rest of tank 309 and on leaving enters cold refrigerant vapor pipe system 71.

Our system is preferably automatic in its normal operation. To regulate the system as a whole, we preferably regulate the flow of refrigerant into the solar coil, the operation of the compressor, the setting of the damper, and the setting of the two pairs of three-way valves which determine for the air coil and the earth exchange respectively whether it shall be operated evaporating or condensing or cut off (or, in the case of the air coil of the brine-tank form of Figure 24, the setting of the three-way valves-which determine whether it shall receive warm or cool brine). Flow into these latter when operated evaporating, and into the water cooler, is also individually controlled. As already explained, automatic control of the earth moistening system is also considered preferable.

Dual solar coil expansion valve 98, besides throttling the refrigerant down, regulates the flow of refrigerant into the solar coil so that, under the particular conditions of radiation and weather obtaining at the time, prplper temperatures will be maintained in the solar co More specifically, in solar coil expansion valve 98, as shown in detail in Figure 10, the liquid will enter by liquid input passage 310 in the side into chamber 311 and then go through valve passage 312 into chamber 313 and out through outlet passage 314 leading toward the solar coil. The supply of refrigerant through the solar coil will be cut off whenever valve member 315 closes passage 312.

The action of this valve member is regulated by the opposition to each other of Sylphon bellows 316 and 317 as affected by compression spring 318, attached to plate 319 which with Sylphon bellows 320 helps close olf chamber 311. Sylphon bellows 316 is filled with refrigerant vapor coming from thermostatic bulb 321 (Figure l) which is in intimate association near the outlet of the solar coil with cold refrigerant vapor piping leading from that coil, communication between bulb and Sylphon bellows being by capillary tube 322. Sylphon bellows 317 is in communication through tube 324 with the interior of the discharge end of the solar coil. Thus Sylphon bellows 316 gets superheat pressure, while Sylphon bellows 317 gets saturated vapor pressure; and sutlicient superheating tends to build up the pressure in Sylphon bellows 3'16 and to make it overcome Sylphon bellows 317 together with spring 318 and open the valve passageway 312 to admit more refrigerant into the solar coil to be heated.

The position of the bottom end of spring 318, and therefore the force the spring exerts at any given position of the valve member, is determined by the action of solenoid 331 on armature 332 which pushes up plate 319. When the solenoid has current running through it, the armature will be brought up into the position shown in the drawing. When the solenoid has no current running through it, the armature will drop, with corresponding effect on the spring compression.

The solar coil expansion valve is readily adjustable. When it is desired to adjust the pressure that spring 318 exerts in its contracted position, this can be done by bringing the solenoidal part of the valve closer to the upper part by means of cooperating screw threads 337 on the two respective parts. This adjustment will also change the spring pressure in its extended position, in which the armature will rest against low temperature adiustment plug 338. independent adjustment of the extended position of the spring is possible as a result of cooperative screw threads 339 by merely turning plug 338.

Control over whether or not current flows through solenoid 331 in the dual temperature expansion valve, is maintained by solar thermostat 3'43 and outdoor ambient temperature thermostat 344. When these two thermostats are both in proper position, electric current will flow through circuit 345, including conductors a, b, c, d and e, between opposite sides 346 and 347 of the line. and thus through the solenoid.

Solar thermostat 343 is subject to approximately the same radiation conditions as radiation-absorbent sheet 32, and also the same conditions as far as heat loss to the outdoors is concerned, but is out of contact both with the sheet and with the solar coil and air passageways so as not to be subject to the same conditions as far as giving up heat for utilization is concerned. The solar thermostat will be set to close its electrical contacts whenever its temperature rises above a certain point, such as for example F., suflicient to heat air flowing under plate 32.

Outdoor ambient temperature thermostat 344 has thermostatic element 348 occupying an intermediate position between contact 349 on dual temperature expansion valve circuit 345, and contact 350 on circuit 351 through stop valve 97. The thermostatic element 348, whose position is adjustable by screw 352, is positioned to close contact 349 on the dual temperature expansion valve circuit when the thermostat falls below a certain temperature, say 70 F.

Forming part of the dual temperature expansion valve circuit 345 is also solenoid 353 which when activated will place damper 244 in the position shown in Figure 4, to allow air to pass through the air passageways 220 under the solar sheet. When it is not activated, the damper will swing into position for the air to by-pass these air passageways. (In the diagrammatic representation of Figure 1, for simplicity of illustration of the electric circuit, solenoid 353 and damper 244 which it actuates are shown away from their actual place with reference to the air circulation system, the actual place of the damper in that system being shown in Figures 4 and 5).

Thus, when the temperature of the solar thermostat is above the temperature set, say 90, and the outdoor ambient temperature is below that set for its thermostat, say 70, circuit 345 will be closed. As a result of closure of the circuit, the damper will be set so that air heated by the solar-radiation-absorbent sheet will be circulated for heating purposes, and at the same time the dual temperature expansion valve will be set so that much higher superheat in the solar coil vapor will be required to open the solar coil expansion valve, since the armature will have compressed the opposing spring 318 into relatively contracted position. Thus, under these conditions, heat can be taken from the solar sheet by means of the circulating air, while at the same time heat-receipt by the refrigerant can be largely limited to times when the rate of heat-absorption by the solar sheet is so great that it is more than enough to heat the air to the desired temperature.

On the other hand, if the solar thermostat is below the particular temperature for which it is set, say 90', or if the ambient outdoor temperature is above that at which its thermostat will close the circuit, say 70", the circuit will remain open, and the damper will be set so that the circulating air will bypass the solar sheet, and the armature of the dual temperature solar coil expansion valve will have fallen so that much smaller superheat will be suflicient to open the valve. Thus as the result of this arrangement, the solar coil will be nearly filled with refrigerant, with less superheating of the vapor, and the solar coil, and therefore the solar sheet, will maintain a much lower temperature, so that by virtue of the lowered rate of heat loss relatively more not heat will be taken in.

When the outdoor ambient temperature rises above a certain temperature, say 75 F., thermostatic element 348 touches contact 350 to close stop valve circuit 351, thus closing stop valve 97 to cut off altogether the how of refrigerant into the solar coil, regardless of how much superheat there may be in the solar coil.

These various solar unit controls will have approximately this overall effect.

When the outdoor ambient temperature is above a certain point, say 75, there will be no fiow of air and refrigerant through the heating portions of the solar unit; the solar unit will have ceased functioning as a source of heat for the rest of the system. Thus, when hot weather makes cooling the primary requirement of the system, any incidental heating needs, as for domestic hot water, will be supplied from the heat removed in the cooling process, raised in temperature by use of the refrigeration cycle, or, insofar as additional heat may be necessary, it will be supplied from the earth.

When the outdoor ambient. temperature is in aninterhas rod 392 extending mediate range, say 70-75, the air will still notbe flowing through the heating portions of the solar coil, but the refrigerant will be flowing at a rate determined by the dual-temperature solar coil expansion valve, thus making heat available from the solar unit for use for such things as domestic hot water supply and for storage for ultimate use at times when solar radiation is not being received in great quantity by the solar sheet.

When the outdoor ambient temperature is below that intermediate range, say below 70, then we must consider the solar thermostat. If the solar thermostat is above a certain temperature, say 90 F., the solar unit will primarily be heating air to be used for heating purposes, but secondarily may furnish excess heat to the refrigerant in the solar coil for the heat pump system. If the solar thermostat is below that temperature, all the net heat available to the solar unit will go into the heat pump system, and at a reduced temperature which will reduce heat losses from the solar unit.

The solar coil expansion valve and the mode of its operation which we have conceived have the great advantage, when heating is required, of flexibly controlling the temperature of the radiation-absorbent sheet in accord with radiation conditions so that when the radiation is sufficient, a temperature will be maintained at which the highly efficient direct transfer of heat by air can be used, and when the radiation is insufiicient for that, nevertheless by maintaining a considerably'lower temperature and thus greatly reducing radiant and other heat losses, the radiation-absorbent sheet can during a very considerable proportion of the daytime be used as a relatively etficient source of heat for the heat pump.

The operation of compressor 87 is controlled by temperature modulation controller 360, shown mostly in Figure 13.

The conducting contactor finger 361 is pivoted at end 362, through which it is electrically connected to one side of the line at 363. Intermediately between its end 362 and its contact area 364 it is attached to modulating rod 365 which is pressed upwardly by gas-filled Sylphon bellows 366, which in turn responds to pressure generated in thermostatic bulb 367 (Figure l), which is outdoors beyond building Wall 368 and communicates with the bellows by capillary tube 369. Counterbalancing the bellows in its pressure on the rod is compression spring 370 seated against disc 371 in well 372 in the upper part of controller casing 373. Since thermostatic bulb 367 is exposed to the outdoor air, the position of contactor finger 361 will depend on the outdoor ambient temperature.

Held respectively above and below finger 361 by end holders 380 and 381 are flexible contacting spring fingers 382 and 383, both electrically connected to the other side of the line at 384 through solenoid 385. Contact pointers 386 and 387 extend from the respective spring fingers toward contact area 364 of intermediate finger 361.

Sylphon bellows 390, connected by capillary tube 391 to the hot high pressure refrigerant vapor pipe system 88, downward from its end toward lower finger 383. Sylphon bellows 393, connected by capillary tube 394 to the warm low pressure refrigerant vapor pipe system 86, has necked rod 395 extending downward past upper finger 382 so that head 405 below the neck 406 will be in a position to raise the finger on upward movement of the rod. Bellows 390 and 393 are opposed in their action by spring fingers 383 and 382 respectively, whose action can be regulated by means of adjusting screws 407 and 408.

Solenoid 385 has armature 410, on the bottom of which is contact plate 411 so arranged as to bridge the gap between contact points 412 and 413 whenever current is flowing through the solenoid. These contact points are in circuit 414 connecting compressor motor 415 (Figure 1) to the line at 363 and 384.

Besides adjusting screws 407 and 408 for the two end fingers, the device has screw 417, which makes possible the adjustment of the setting of the middle finger for a given pressure in Sylphon bellows 366, by fixing the position of disc 371 which is seated against the lower end of the screw, and thus determining the force exerted by spring 370 at any given position of modulating rod 1365..

Flexible fingers 382 and 383 are so positioned that contact pointers 386 and 387 are in contact with intermediate finger 361 whenever they are not held away from contact by rods 392 and 395. When either orboth,

of these contact pointers are in contact, solenoid 385 will close the compressor motor circuit, causing the compressor to operate. If the pressure in the high pressure side is high enough for the end of rod 392 to push the lower finger to a position where its pointer will be out of contact, and at the same time the low pressure side pressure is low enough for head 405 to pull the upper finger sufi'iciently to break its pointers contact, the solenoid circuit will be broken and the compressor will cease operation..

Thus, the modulating controller will regulate the high and low side pressures of the heat pump system by keepmg the compressor operating as long as the pressure in either side requires it. Thus, refrigerant pressures will be maintained to meet the heating and cooling demands of the building and other demands such as those due to heating or cooling water and to temporary heat storage.

Furthermore, the controller will modulate its regulation in accordance with the outdoor ambient temperature. To meet cold weather, the lower the outdoor ambient temperature is, the lower in position the middle finger of the controller will be, and the higher the high pressure side of the system will be kept by the regulator, thus meeting the increased heating load. At the other extreme, to deal with hot weather, the higher the outdoor ambient temperature is, the higher in position the middle finger of the controller will be, and the lower the low pressure side of the system will be kept by the regulator, thus meeting the increased cooling load. In the intermediate temperatures, where such great capacity is not required, the less extreme the temperature, the less extreme will be the high and low side pressures maintamed, and the more efiicient will be the operation of the system as a result.

Thus with the less extreme outdoor temperatures, the greater efliciency inherent in smaller pressure differential between the high side pressures and the low side pressures will be secured, while with the more extreme outdoor temperatures, the greater capacity inherent in more extreme pressures will be gotten. We will thus automatically have a highly effective and flexible accommodation of the system to the requirements imposed by the Weather.

The spec1fic pressure ranges to be used in such a system Wlll obviously depend upon various factors, includlng such things as the refrigerant used and the capacity of the system relative to the load expected. Where Freon 1s used as a refrigerant, a typical high side pressure range would be 200 to 250 pounds gauge pressure, and a typical low side minimum pressure would be 35 pounds gauge pressure.

Needless to say, adequate insulation will be required on those parts of the refrigerant system where loss or gain of heat is undesirable.

To control thermal communication between the re- 424 consisting of flexible element 42 near the pivot and of rigid element 426. Against 1s arrn presses compression spring 427 seated on nut 428, which in turn rides on screw 429 for purposes of ad ustment. In theother direction, pressing against the side less leverage than Sylphon bellows 431 connected to the low pressure side, in a proportion to be determined by the exact characteristics desired.

Evaporat ng circuit contact 432 is phon bellowsside of the rigid element of the arm, and coindensmg circuit contact 433 is put on the opposite si e.

The arm is made of electricall conductin and is connected g material Evaporating circuit contact 432 is connected by suitable three-way valves 121 Condensplaced on the Sylmasses earth tube with a selected part of the rest of the refrigerant system as already detailed.

When the arm is in neutral position-that is, when it does not touch either of the two opposite contactsthe fact that the circuits through it are open will cause the three-way valves to be closed, thus shutting off the how of refrigerant between the rest of the refrigerant circuit and earth tube 123 (using the form of Figure l as an illustration). Closing the evaporating or the condensing electric circuit by closing of the corresponding contact against arm 424 will set the three-way valves to permit flow of refrigerant through the earth tube to operate it evaporating or condensing, as the case may be, with the aid of refrigerant connections which have al ready been described. By having the three-way valves 121 and 126 electrically in parallel and controlled from points in common on the circuits they will operate in tandem, changing their settings simultaneously.

In the forms of Figures 17 to 19 and 21 to 23, of course, such three-way valves would control the refrigerants access to tank 155 or cellar floor coil system 149, or refrigerant tube 261, as the case may be, rather than the earth tube. In Figures 17 and 18 the three-way valves actually shown, 121' and 126', vary slightly from corresponding three-way valves 121 and 126, respectively, in that 126 is shown without any electrical connections. In this alternative form, instead of the two valves being made tandem in their operation by electrical means as in the case of 121 and 126, 126 would be held in tandem with 121 in some other way, as by mechanical connections. It will be understood that such a method of keeping them in tandem could equally well be applied to any other pair of three-way valves which are here shown as electrically in tandem.

The differential switch operates as follows, as illustrated with reference to the system of Figure 1: When the weighted average of high and low pressures falls below a certain predetermined point, movement of the arm toward the evaporating circuit contact will complete the circuit to throw three-way valves 121 and 126 into position to make the earth tube an evaporator. Likewise when the weighted average of these pressures goes above a certain point, a circuit will be established through condensing contact 433 and intermediate contact 438 to operate the three-way valves so as to have the earth lube operate as a condenser. Adjustable screw 445 is placed so as to break the contact between condensing contact 433 and intermediate contact 438 when the Lveilghted average of these pressures becomes sufiiciently By means of this control, it will be possible automati cally to operate the system so that whenever the condition of the system is such that heat should be put into the earth, either for temporary storage, or, as during summer cooling, for gradual ultimate dissipation, the heat exchanger will operate condensing for that purpose, and whenever the system needs heat from the earth, the heat exchanger will operate evaporating so that the system will obtain it. This makes it possible to take heat which is orginally received as radiation by the solar unit at a time when the building does not need it and automatically store it in the earth and then later draw on it for use when needed.

Three-way valves 99 and 92 governing the air coil 91 (Figure l), or, in the form of Figure 24, three-way valves 270 and 273 governing the air coil 272, are desirably similar in their makeup to those governing the earth tube, and operated in tandem by similar means. Control over them is secured by indoor thermostat 451 having thermostatic element 453. Below a certain temperature this thermostatic element will close hot contact 454 closing circuit 455 and thus setting the three-way valves to make the air coil operate as a condenser. Above a certain temperature it will close cold contact 456 closing circuit 457 to set the three-way valves to make the air coil operate as an evaporator. Heat then extracted from the house air is delivered into the earth or used when required for heating water.

The expansion valves (242 and 127 respectively) used in connection with the air coil and the earth tube or other earth heat exchange when operated evaporating. and expansion valve 307 used with the water cooler, all have individual thermostatic controls. Eachof these suitably consists of a thermostatic bulb 460 intimately associated with the outside of the discharge tube of the heat exchanger being used as an evaporator, a capillary tube 461 leading from the bulb back to the expansion valve, where Sylphon bellows 462 (Figure 11) with which it is connected is balanced against both spring 463 and another Sylphon bellows 464 which communicates by tube 465 with the interior of the discharge tube of the evaporator. As the superheat increases, Sylphon bellows 462 overbalances the forces against it and opens the valve to admit more refrigerant liquid into the evaporator; when the superheat diminishes, the valve tends to close, decreasing the flow of refrigerant.

With out repeating the more specific description of the operation of the system, as already treated in connection with the description of the system itself, the following are some of the salient features, in a generalized way, of the operation of our system from an overall standpoint, as used for example in the heating of a building.

During those times when the outdoor temperature makes heating the prime requisite, the way the system operates at any given time will depend on the amount of solar radiation being received.

When a relatively large amount of radiation is being received, heat received by the solar-radiation-absorbent sheet 32 (Figures 4 through 8), will be taken mainly into the air in the passageways 22f) beneath it and thence passed into the building to be heated at the relatively minor cost of the forced circulation involved. Insofar as necessary, this will be supplemented by heat conveyed from the solar coil 33 in solar unit 31 by heat pump action at a relatively high coefiicient of performance. Excess heat not needed to heat the building will be taken, either directly from the solar coil or from the heated air passing through the air coil into the building, by the heat pump and delivered into the earth beneath or adjacent to the building for temporary storage. The process of storage and of later use is greatly facilitated by the automatic maintenance of proper moisture content in the earth contacting and near these surfaces where heat exchange with the earth takes place.

When the radiation falls off to intermediate values, action of the solar thermostat 343 will result in shutting off the passage of the air through the solar unit and the system will get its heat from the solar coil in the solar unit by the heat pump action. Reduction of the temperature of the solar coil as automatically controlled by the dual temperature solar coil expansion valve 98 and solar thermostat 343, will enable the heat-gathering potentialities of the solar coil relative to the rate of radiation received to be greatly increased, at the expense, somewhat, of a decrease in the coefficient of performance. The coelficient of the system can, however, still be maintained by this means above the actual working coeflicient of performance of other heat pump systems using natural heat sources under similar climatic conditions. Any excess heat gathered will be temporarily stored in the earth, as before.

Throughout the above conditions, heat from radiation by way of the heat pump can be used also to meet hot water requirements.

, When the net heat received from radiation becomes too small to meet heating needs, heat will be provided by the system itself within the building. The amount of this stored heat may deliberately be made large enough to tide the building over peak electrical power periods without operation of the compressor, as by use of the large brine tank 269 as part of the interior system, or by a large hot water heat accumulator tank, as with a sufficiently large version of tank 102, or by Glaubers salt tank 286.

As further heat becomes needed when radiation is insufficient, the system will draw on the adjacent earth by means of its own heat pump action. The presence of the temporarily stored heat in the earth will enable it to do this at temperatures much increased over what the earth temperature would be if the same earth facilities were used without intermittent heat storage.

Thus the capacity of a given earth installation will be greatly increased. Furthermore, use can thus be made of heat coming from a solar radiation receiver at relatively high temperature and temporarily stored in the earth at a relatively high temperature, in place of heat that would otherwise have to come from the earth at earth temperatures that are at best normal, and very often greatly depressed as a result of the operation of the heat pump. As a result, with proper operation of the system, a

considerably increased coeflicient of performance is possible.

Along with its capabilities in heatin the system always stands ready, by proper use of its refrigerant circuit, to meet cooling needs such as, more especially, the cooling of the building during warm and hot weather, and also the cooling of drinking water. I

The word foundation as used in the claims is intended to refer generally to any partitioning walls or floors in a building which are in contact with the earth on at least one side, whether they are intended to support the building, or are for some other purpose, such as separating the cellar interior from the surrounding earth.

The phrase expansion valve, as used in the claims herein, is used broadly to include any device for reducing the pressure of fluid passing through, regardless of whether or not it also has the power to cut off or regulate flow through it.

The word fluid as used in the specification and claims is used in its normal dictionary significance, to cover both liquids and vapors or gases.

The word surface, as used in the claims in connection with the receiving or absorption of heat or radiation includes a part of a radiation-absorbent material which substantially abuts on radiation-pervious material or a vacuum, regardless of whether the radiation-pervious material is gaseous, liquid or solid.

In view of our invention and disclosure variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of our invention without copying the process and structure shown, and we, therefore, claim all such insofar as they fall within the reasonable spirit and scope of our claims.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

l. A heating system comprising a heat receiver relying mainly on radiation from outdoor sources including the sun, a heat pump operable to transfer heat from the re ceiver for utilization and having an evaporator, a compressor, a condenser and an expansion valve through which refrigerant-type fluid flows in circuit, a first sensing element operative at least partly in accordance with the rate of net heat intake into the heat receiver from the outdoors assuming a given refrigerant temperature, a second sensing element operative at least partly in accordance with the evaporator exit temperature of the refrigerant-type fluid, and a flow control for the, refrigerantt'ype fluid, said control having an action which is dependent at all times at least partly on the second sensing element but said control having its particular setting relative to that second element subject to be changed by the first sensing element.

2. In a heating system, a solar radiation heat receiver, an air circulation system operable to draw air from a position Where it is heated from the receiver and transmit it for heating utilization, a heat pump operable to receive heat from the receiver and supply it for utilization, a sensing element responsive in accordance with the net rate of heat receipt by the heat receiver, and a control over the relative amount of activity as between the air circulation system and the heat pump, which control is affected by the sensing element.

' 3. A heating system comprising a solar radiation heat receiver, an air circulation system intermittently operable to take for heating utilization air which is heated by the receiver, a heat pump operable to receive heat from the receiver and supply it for utilization, a thermostat responsive in accordance with the net radiant heating conditions at the heat receiver, and a control subject to the thermostat which control concomitantly acts to make the air circulation system take for heating utilization air which is heated by the receiver and to increase the temperature of heat receipt by the heat pump.

4. A heating system comprising a solar radiation heat receiver, an air circulation system operable to draw air heated by the receiver and transmit it for utilization in heating, a heat pump operable to transmit for utilization heat from the receiver with a boost in temperature, a thermostat responsive in accordance with outdoor ambient temperature, a second thermostat responsive in accordance with the net rate of heat receipt by the heat receiver, a first control means responsive in accordance -yvith theamount ofsuperheat in theevaporator of the heat pump governing the rate of intake of refrigerant into the evaporator and a second control means under the joint control of said thermostats controlling the action of the air circulation system and the heat pump and the setting of the first control means, whereby when the outdoor ambient temperature is below a predetermined value and at the same time the net rate of heat receipt is above a predetermined value, the air circulation system operates as above specified and when the outdoor ambient temperature is below a second predetermined value, the heat pump operates as above specified and when the net rate of heat receipt by the heat receiver is below the said predetermined value the temperature boost by said heat pump is increased.

5. In a heating system for a building, a solar heat receiver to convert solar radiation into heat by absorption, a heat pump utilizing a fluid medium capable of acquiring and surrendering heat and having for said medium an evaporator which receives heat from the receiver and having a compressor and then a condenser for said medium after it has passed through the evaporator, and an air circulation system having an air duct leading from heat transfer relation for the air with the receiver through heat transfer relation for the air with the condenser to a position for the air to dispense heat to the building and having a fan to drive the air and a by-pass damper to permit the air to by-pass the receiver.

6. In a system for furnishing heat to a building, a solar radiation heat receiver, a heat pump circulating mechanical-refrigeration-type fluid and having an evaporator deriving heat from the receiver, a compressor having an intake and an outlet, a condenser and at least one expansion valve, a heat dispenser dispensing heat from the condenser to the building, a heat exchanger having a first fluid passage and a second fluid passage in heat exchange relation with each other, means for connecting the first passage to receive mechanical-refrigeration-type fluid from the outlet of the compressor, a liquid circulating system circulating liquid from the second fluid passage to a point in heat exchange relationship with the earth and return, and means operable to disconnect the first.

fluid passage from the compressor and connect the first fluid passage both to receive mechanical-refrigeration-type fluid from a said expansion valve and to direct fluid from the outlet of the heat exchanger to the intake of the compressor.

7. In a heating and cooling system, a radiation-absorbent surface especially adapted and positioned to receive solar radiation in quantity, radiation-pervious insulation above the surface to substantially reduce iconduction and convection losses therefrom, an air conduit leading from a position for air to be heated from the radiation-absorbent surface to a position for utilization of air for heating and cooling purposes, means to cause air flow through the conduit toward the position for utilization, valving means in the conduit operable to out 01f the air heated from the radiation absorbent surface and admit other air instead, a refrigerant evaporator receiving heat from the radiation-absorbent surface, an expansion valve supplying refrigerant to the evaporator, a compressor drawing refrigerant from the evaporator and increasing the pressure of the refrigerant, a refrigerant tube in heat exchange relation to the air in the conduit, a second refrigerant tube in intercommunication with the earth, the tubes each having connections openable to receive refrigerant from the compressor for condensation within the tube and to supply the condensed refrigerant to the expansion valve and each having connections openable to receive, for evaporation within the tube, intermediately expanded refrigerant from the other tube operating as a condenser and to supply evaporated refrigerant to the compressor, means to shut and open the tube connections, a first sensing element responsive in accordance with the net rate of heat input to the heat-absorbing structure, subject to this first sensing element a first control unit for both the conduit valving means and the evaporator, a sensing unit responsive in accordance with an integration of refrigerant pressures on both sides of the compressor, subject to this sensing unit a second control unit for the connection of the second tube which determine when it shall operate condensing and also when evaporating, a thermostat responsive to the temperature of what is to be heated and cooled, and subject to this thermostat a third control unit for the connections ofthe first tube which $9 determinewhen-it shall 'operate'condensing and also when evaporating.

8. In a mechanical-refrigerationcycle heating or cooling systemthat uses heat transfer to or from-the-earth, a structure extending downward into the earth and comprising three concentric tubularwalls forming three -passages two .of which intercommunicate the lower part of the structure with each other and contain a fluid heattransfer -medium, and the thirdof which communicates in-thelower part-of thest-ructurewith the earth andconducts water tomoisten the earth and thus facilitate .heat exchange with the earth'and in'the system a pump which induces -flow of the refrigerant fluid through the intercommunicating passages.

9 =In a-mechanical-refrigeration-cycleheating or cooling system which exchanges heat with the earth, a heat exchanger incontactwiththe earth, afirst temperature sensing element in contact with the heat exchanger, a second temperature sensingelement located in the earth in-theneighbor'hood of but substantially spaced from, the heat exchanger, anearth-moistening unit adapted to impart moisture to earth which is between the heat exchanger aud'the secondtemperature sensing element, and a control for the earth mojistening unit which control regulates the operation of the unit in accordance with the amountiof-difference in-the temperatures so sensed.

10. In aheating system-,a solarradiationheatreceiyer, and..a heat pump circuit-comprising a refrigerant evaporatorlheated from-the receiver, a compressor connected with the evaporator to receive refrigerant from it, a condenser connected with the compressor to receive refrigerantfrom it and-giving up heat for utilization, refrigerant return connection from-the condenser to the evapora tor, a refrigerant tubeinthermal intercornmunication with the earth-and-havingconnections openable to put it in the position of a-condenser in the circuit and connections openable to put-it lin theposition of an evaporator in the circuit, 'and expansion =valving means in the circuit for the evaporator and for the tube =when.connected in the position ofan evaporatoriin the circuit, whereby heat from solar radiation may be :taken-into the circuit and some of .it utilized without anyoutside storage while some of it is stored interrnediately-in the earth and utilized subsequently.

ll. iln heat receiver, a mechanical-refrigeration-cycle heating unit having anevaporator taki 'heattfromthe heat receiver, a compressortanda condenser in heat transmission relationshiprwith the:building a refrigerant conduit in heat exchangerelationship-with theearthand having a three-way valve atreach ;end,.c onnections from ;the heating unit to the three-way valvesputting therefrigerantconduit in the samepositionin .the mechanical refrigeration circuit as theevaporatorifortone settingiof the valves, and connectionsfrom the:heatingtunititozthe three-way valves putting the refrigerant conduit in the same position in the mechanical refrigeration circuit asitheicondenser for another setting ,of the valves, :whereby zheat may be passed :between rheating'systemand earth at will.

.12. :In an ainconditioning system,axbu ilding having an interior, :a solarradiationgheat receiver, a heat exchanger adapted ;to exchange heat withthe-earth, a heat exchanger withthe building interior, and:a mechanical-refrigerationcycle ,heating and cooling :unit having an evaporator in heat transfer relationship with ;the heat receiver, a compressor, pipes providing the unit both evaporating and condensingaccess to ;the. earth heat exchanger, three-way valves for the pipes ;having one position in which both acc s es to the .earth heat exchanger are closed, another position inwhich evaporating access'with the earth heat exchanger is open but condensing access-with it closed, and a third positionin which condensing access with the earth heat exchanger is .open but evaporating access with it closed, other pipes providing the unit both evaporating and condensing access to the heat exchanger with the building interior, and thermostatically controlled threeway valves for these other pipes having one position in which-both accesses tothe building interior heat exchanger are closed, another positionin which evaporating access with the building interior heatexchanger is open'but condensing access with itclosed, and a third position in which condensing access with the building interior heat exchanger :is open but evaporating accesswith it closed,

13. In a heating and cooling-system, a metallic sheet especially adapted and positioned to receive. solar radiaa'heating system;for a building, a solar radiation tion, .a :layer of radiation-pervious paneling :above :and spaced from the sheet, a second such layer above :and spaced from the first, partitioning varound the edges .of thespaces between sheet, first:layer.-and secondlayer, walls cooperating withthetunderside of'the sheet to form a heatreceiving air passageway, an air conduitleading from the air passageway to a position for utilization of the .air therein for heating and cooling purposes, a dampertoperable to cut off the connection of the conduit with the passageway and admit air to the conduit from sometother place, a blower tocirculate airinto and through the conduit, a refrigerant-evaporating coil in extensiveicontact with the sheet, a compressor connected to receive refrigerant vfrom the tevaporatingcoil, a three-way .valve connected to receive refrigerant ,from the compressor, a second refrigerant coil in heat exchange relation to. the :air in the conduit andconnected .to .operate as a condenser receiving refrigerant from the compressor ithrough the three-.wayvalve, a second three-way valve operating in tandemwith the firstand connectedtto receive refrigerant from the second coil, an expansion valve connected to receive refrigerantfrom the second :three-way valve and supply it to the first coil, a thirdthree-way valve-connected to,receive refrigerant from the compressor,-a-tube in thermal intercommunieation with :the earth and connected to operate as a condenser receiving refrigerant from the compressor through the third three-way valve, 'a :fourth three-Way valve operating in tandem with the third and connected :to :receive refrigerant from the tube and to supply it-to the expansion valve, a second expansion valve connected to receive refrigerant from the second threeway valve, the third and fourth three-way valves being conneeted'also fortoperationof the ,tube as an evaporator, one of them to receive refrigerant from the second expansion valve and the-other to supply refrigerant to the compressor, the tandemoperationof the said two valves being such asin normal operation to close off the connections-iof the tube foroperation as anevaporator .during substantially all the timetwhen its connections for operation condensingare open and to close-off the connections of the rtube for operation as a condenser during substantially all the time when ;its connections for operating evaporating are open, and a third expansion .valve connected ,to receive refrigerant from the fourth three-way valve, the first two three-way-valves being also connected for operationof the-second coilasan evaporator, one of them toreceive-refrigerant fromthethird expansion valve andthe-other to supply it to the compressor, the tandem operation of the first two valves being such as innormal operation to close off the connections of the second coil fortoperationas an evaporatorduringsubstantially all the time when its connections for operating condensingare open and to close off the connections of the second coil-for operatingcondensing during substantially all the time when .its connections for-operating evaporating are open.

.14. I a heatingsystem, a solar radiation heat receiver, anda heatpump including the following a hcatexchange tube .in.;thermal intercornmunication with .the earth, an evaporator in thermal intercommunication with theheat receiver, a-condenser in thermal intercommunication with what .is to be,heated, a;compressor interconnected to receive refrigerant-type fluid from the evaporator and to pass it to the condenser, pressure, reduction means interconnected to ,receive such fluid .from .the condenser and to pass itonto the evap0rator,.a;first interconnection for refrigerantatypetfluidfrom compressor to the above-mentioned tubein thermal intercommunication with the earth to operatethe tube condens'inga secondjnterconnection from the pressure reduction means to the said tube and thence to the compressor intaketo operate the said tube evaporating, valving means on said first andsecondtinterconnections having a position -'in which the first alone of them isropen, a position in which thesecond alone of them is open, and a position in which both are closed and .a control for the valv'ingmeans which control includes ,two pressure-responsive partitions and ,an element having at least three positions, one of the partitions being responsive to the pressure of the refrigerant after it passes through the compressor but before it next passes through the pressure reduction means and the other to the pressure of the refrigerant after it passes through the pressure reduction means but before it next passes through the compressor'and eachpartition beingbiased to tend to produce movement of the control element in the same direction, and means by whichthe control'element in each one of 

